title: Effects of high hydrostatic pressure on enzymes, phenolic compounds, anthocyanins, polymeric color and color of strawberry pulps.
abstract: BACKGROUND
  Changes in activity of polyphenol oxidase (PPO), peroxidase (POD) and β-glucosidase, individual phenolic compounds other than anthocyanins, total phenols, monomeric anthocyanins, polymeric color and instrumental color of strawberry pulps were assessed after high hydrostatic pressure (HHP) (400-600 MPa 5-25 min(-1)) at room temperature.
  
  
  RESULTS
  β-Glucosidase was activated by 4.7-16.6% at 400 MPa 5-25 min(-1) and inactivated by 8.0-41.4% at 500 or 600 MPa. PPO and POD were inactivated at all pressures, the largest reduction in activity being 41.4%, 51.5% and 74.6%, respectively. The individual phenolic compounds and total phenols decreased at 400 MPa, but total phenols increased at 500 or 600 MPa. However, the monomeric anthocyanins, polymeric color and redness (a*) exhibited no change. HHP induced a decrease in lightness (L*) and an increase in yellowness (b*) at 400 MPa, but no significant alteration in L* value and b* value at 500 or 600 MPa was observed; this was attributed to higher residual activity of PPO, POD and β-glucosidase at 400 MPa. Total color difference (ΔE) was ≥5 at 400 MPa and ≤3 at 500 or 600 MPa.
  
  
  CONCLUSIONS
  HHP effectively retained anthocyanins, phenolic compounds and color of strawberry pulps, and partly inactivated enzymes.
authors.affiliation: College of Food Science and Nutritional Engineering, China Agricultural University, China.
authors.forename: Xiamin
authors.initials: X
authors.lastname: Cao
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Fusheng
authors.initials: F
authors.lastname: Zhang
authors.forename: Yongtao
authors.initials: Y
authors.lastname: Wang
authors.forename: Jianyong
authors.initials: J
authors.lastname: Yi
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Liao
mesh_terms: D000872:Anthocyanins / Q000378:metabolism*; D004156:Catechol Oxidase / Q000378:metabolism; D003116:Color; D004798:Enzymes / Q000378:metabolism*; D031985:Fragaria / Q000201:enzymology / Q000378:metabolism*; D005638:Fruit / Q000378:metabolism*; D006874:Hydrostatic Pressure; D009195:Peroxidase / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D011108:Polymers; D001617:beta-Glucosidase / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D004798:Enzymes; D010636:Phenols; D011108:Polymers; D004156:Catechol Oxidase; D009195:Peroxidase; D001617:beta-Glucosidase